Control apparatus, control method, and medical support arm apparatus

Abstract

[Object] To enable further suppression of the movement amount of an arm section when switching states. [Solution] There is provided a control apparatus configured to execute a current tracking control on a basis of a measurement value of a torque sensor of an actuator provided in at least one of multiple joint sections included in an arm section of a medical support arm apparatus, the current tracking control causing a motor of the actuator to output torque by which a position and an attitude of the arm section are maintained, and switch a first state in which the motor is driven in accordance with a predetermined control method, and a second state in which the joint section is locked using a brake of the actuator.

The invention claimed is: 
     
       1. A control apparatus, comprising
 circuitry configured to 
 execute a current tracking control based on a torque of an actuator in at least one joint section of multiple joint sections in an arm section of a medical support arm apparatus, the current tracking control causing a motor of the actuator to output torque to maintain a position and an attitude of the arm section, and 
 during the current tracking control, switch between a first state in which the motor is driven in accordance with a predetermined control method and a second state in which the joint section is locked using a brake of the actuator, wherein 
 the actuator includes an encoder that measures a rotational angle of a drive shaft of the motor, and 
 the circuitry is configured to detect an abnormality of the motor or the brake on a based on the rotational angle. 
 
     
     
       2. The control apparatus according to  claim 1 , wherein
 the actuator is an actuator with a built-in brake, the actuator having the brake attached to an input shaft. 
 
     
     
       3. The control apparatus according to  claim 1 , wherein
 the circuitry is configured to decide a timing at which to end the current tracking control based on the rotational angle. 
 
     
     
       4. The control apparatus according to  claim 1 , wherein
 the circuitry is configured to detect an abnormality of the motor based on the rotational angle while the brake is being released. 
 
     
     
       5. The control apparatus according to  claim 1 , wherein
 the circuitry is configured to detect an abnormality of the brake based on the rotational angle when the at least one joint section is being locked by the brake. 
 
     
     
       6. The control apparatus according to  claim 3 , wherein
 the encoder is an output shaft encoder that measures a rotational angle of an output shaft through a speed reducer of the motor. 
 
     
     
       7. The control apparatus according to  claim 1 , wherein
 in the current tracking control, the circuitry is configured to compute a current value for each motor using a torque constant unique to each motor of each joint section and supply the current value to each motor. 
 
     
     
       8. The control apparatus according to  claim 1 , wherein
 the circuitry is configured to switch between the first state and the second state at mutually different timings for each joint section. 
 
     
     
       9. The control apparatus according to  claim 8 , wherein
 the circuitry is configured to decide timing of switching between the first state and the second state for each joint section based on at least one of a configuration of the arm section, and the position and the attitude of the arm section when switching states. 
 
     
     
       10. The control apparatus according to  claim 1 , wherein
 a medical tool used in a medical procedure is provided on a front end of the arm section. 
 
     
     
       11. The control apparatus according to  claim 10 , wherein
 the medical tool is an imaging unit for imaging and performing enlarged observation of an operative site of a patient. 
 
     
     
       12. The medical support arm apparatus according to  claim 1 , wherein
 the encoder is an output shaft encoder that measures a rotational angle of an output shaft through a speed reducer of the motor. 
 
     
     
       13. A control method, comprising:
 executing a current tracking control based on a torque of an actuator in at least one joint section of multiple joint sections included in an arm section of a medical support arm apparatus, the current tracking control causing a motor of the actuator to output torque maintain a position and an attitude of the arm section; 
 during the current tracking control, switching between a first state in which the motor of the actuator is driven in accordance with a predetermined control method and a second state in which the at least one joint section is locked using a brake of the actuator, wherein the actuator includes an encoder that measures a rotational angle of a drive shaft of the motor; and 
 detecting an abnormality of the motor or the brake on a based on the rotational angle. 
 
     
     
       14. A medical support arm apparatus, comprising:
 an arm section including on a front end to which a medical tool is to be secured; and 
 control circuitry configured to control an operation of the arm section, wherein the control circuitry is configured to
 execute a current tracking control based on a torque an actuator provided in at least one joint section of multiple joint sections included in the arm section, the current tracking control causing a motor of the actuator to output torque to maintain a position and an attitude of the arm section, and 
 during the current tracking control, switch between a first state in which the motor is driven in accordance with a predetermined control method and a second state in which the at least one joint section is locked using a brake of the actuator, wherein 
 
 the actuator includes an encoder that measures a rotational angle of a drive shaft of the motor, and
 the control circuitry is configured to detect an abnormality of the motor or the brake on a based on the rotational angle. 
 
 
     
     
       15. The medical support arm apparatus according to  claim 14 , wherein
 the actuator is an actuator with a built-in brake, the actuator having the brake attached to an input shaft. 
 
     
     
       16. The medical support arm apparatus according to  claim 14 , wherein
 the control circuitry is configured to decide a timing at which to end the current tracking control based on the rotational angle. 
 
     
     
       17. The medical support arm apparatus according to  claim 16 , wherein
 the encoder is an output shaft encoder that measures a rotational angle of an output shaft through a speed reducer of the motor. 
 
     
     
       18. The medical support arm apparatus according to  claim 14 , wherein
 the encoder is an output shaft encoder that measures a rotational angle of an output shaft through a speed reducer of the motor.